Aluminum Castings Heat Treatment

Heat Treatment is one method
used to improve the mechanical and physical properties
of an aluminum casting. Heat Treatment consists of the
heating and cooling of a casting in a controlled and
specified manner, which does not change or affect the
shape of a casting. Heat Treatment not only improves
the strength, hardness and electrical conductivity of
an aluminum casting but it also helps to improve other
manufacturing processes such as machining. Heat
Treatment must be conducted in properly designed
furnaces that provide the internal thermal conditions
and temperature controls to meet strictly specified
guidelines and controls.

The Stages of Heat Treating
Aluminum Castings:

Solution
Heat Treatment - consists of heating an
aluminum alloy casting to a high temperature for a
desired amount of time. After the casting is heated to
a high temperature it is rapidly quenched, by
immersing the entire casting in a water or water
glycol solution. This process is usually done to
increase the strength of a casting

Artificially
Aging Aluminum
Castings � consists of heating an alloy for an
extended amount of time. During the Artificial Aging
process the castings are heated for a specified period
of time but to a much lower temperature ten the
Solution Heat Treatment process. By maintaining the
heating process for an extended amount of time the
grain structure is refined, producing much greater
strength properties of the castings. Artificial Aging
is used to create a harder casting. The Artificial
Aging speeds up the process of aging of a casting that
would normally occur naturally over several years.

Semi-Permanent Mold Aluminum Castings

The Semi-Permanent Mold Casting
process uses the same general procedures as Permanent
Mold Casting but in this process expendable cores of
sand or other materials are added to the molding
process to create a desired shape or an internal
passage. In many cases, the practicality of having a
solid casting does not exist. Many customers require
that a product have passageways for materials to flow
through; therefore a method of creating such
passageways must be incorporated. In Semi-Permanent
Mold Castings a pre-formed core is inserted into the
Permanent Mold cavity. The metal flows around the
insert and creates the desired shape or passageway. By
using a sand core it allows for the easy removal of
the insert to create the desired effect